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Live Coral cover in Gulf of Mannar down to 27%

Live Coral cover in Gulf of Mannar down to 27%

  • Climate change and anthropogenic pressures are overpowering corals’ resilience, but Tamil Nadu forest department’s community-based initiatives have come as a ray of hope.
  • The Gulf of Mannar on the southeast coast of India is a major reef region with a significant spatial extent of corals.

Key Highlights

  • The islands and the surrounding shallow coastal waters were declared the Gulf of Mannar Marine National Park (GOMMNP) by the Tamil Nadu government in 1986.
  • The beautiful looking coral reefs not only serve as nursing grounds for fishes, but act as natural submerged breakwaters providing coastal protection and flood reduction through wave breaking.
  • The Inter-Governmental Panel for Climate Change (IPCC) has predicted that global coral reefs would decline by 70-90% with global warming of 1.5°C by 2100 and go extinct, if it is 2°C or higher.
  • During the recently concluded TN Climate Summit 2.0, a study report titled: ‘Coral reefs of the Gulf of Mannar: was released.
  • It showed that the live coral cover in the region had decline from 37% in 2005 to 27.3% in 2021.

Chief drivers

  • Coral bleaching and ocean acidification due to climate change were primary reasons behind this colossal loss.
  • Annual surveys between 2005 and 2021 show that the coral cover was increasing and reached an all-time high of 42.9% in 2009.
  • The complete halt of coral mining activities after the 2004 Indian Ocean tsunami increased the trend.
  • Shingle island suffered the most with the loss of 72% of its coral cover followed by Krusadai and Pullivasal islands, which lost more than 55%, as per the SDMRI report.
  • Going by the climate models, there would be severe coral breaching this year.
  • Besides this, mechanised trawling, push net operation, shore seine, trap fishing, surface-supplied diving, spear-fishing, purse seine, bottom settling gill nets, ornamental fish collection
    • And seaweed collection are some fishing activities that damage the fragile reef ecosystems of the Gulf of Mannar.
  • However, the primary threats responsible for the declining trend are coral bleaching events
    • Disease outbreaks, algal blooms and invasion of the exotic red alga, Kappaphycus alvarezii.

Saving sinking islands

  • Vaan island.
  • The island had split into two due to severe erosion after which artificial reef modules were deployed, which worked like magic.

Community engagement reduces anthropogenic pressure

  • To reduce the anthropogenic pressures on the reserve, green jobs are being created by providing concessional micro-credit a small amount of capital to fund alternative livelihood.
  • Community-based eco-tourism is one of the methods to generate new green jobs.
  • Last year, UNESCO has awarded Bakan the 2023 Michel Batisse Award for Biosphere Reserve Management.

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